<div dir="ltr">Yashil, <div> </div><div>Thanks very much for that.</div> <div>My real intention is to be notified when the playback reaches a given frame number, instead of doing seek.</div><div>But even though, it is going to be very useful on solving another issue in a near future.</div> <div> </div><div>Thanks again,</div><div>Marcus</div> <div> </div><div> </div></div><div class="gmail_extra"> <div class="gmail_quote">On Mon, Nov 4, 2013 at 3:57 AM, Yashil <<a href="mailto:yashil1@yahoo.com" target="_blank">yashil1@yahoo.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Marcus Nascimento wrote <div class="im">> Hi Yashil, > > I'm very interested in this solution too. > I believe you are a bit ahead of me. > Please, let me know if you find a good solution. > > If I manage to do it, I'll let you know. > > Thanks very much, > Marcus </div>Here is my sample code. It grabs two frames from given video file and displays it by opencv. The first frame seek is done by given frame number and the second frame seek is done by given time position. It works for several codecs in my tests but I have not been able to make it work for mpeg2-ts files yet. MyGstFrameCap1.cpp /**********************************************************************/ // gstreamer includes and libraries #include <gst/gst.h> #include <gst/app/gstappsink.h> #pragma comment( lib, "gstreamer-1.0.lib" ) #pragma comment( lib, "glib-2.0.lib" ) #pragma comment( lib, "gobject-2.0.lib" ) #pragma comment( lib, "gstapp-1.0.lib" ) /**********************************************************************/ // opencv includes and libraries #include <opencv2/opencv.hpp> #ifdef _DEBUG #pragma comment( lib, "comctl32" ) #pragma comment( lib, "opencv_core246d" ) #pragma comment( lib, "opencv_highgui246d" ) #ifndef _DLL #pragma comment( lib, "zlibd" ) #pragma comment( lib, "IlmImfd" ) #pragma comment( lib, "libjasperd" ) #pragma comment( lib, "libjpegd" ) #pragma comment( lib, "libpngd" ) #pragma comment( lib, "libtiffd" ) #endif #else #pragma comment( lib, "comctl32" ) #pragma comment( lib, "opencv_core246" ) #pragma comment( lib, "opencv_highgui246" ) #ifndef _DLL #pragma comment( lib, "zlib" ) #pragma comment( lib, "IlmImf" ) #pragma comment( lib, "libjasper" ) #pragma comment( lib, "libjpeg" ) #pragma comment( lib, "libpng" ) #pragma comment( lib, "libtiff" ) #endif #endif /**********************************************************************/ void MyfCopyRGBbuf2CvMat( cv::Mat& oMatFrameInp, unsigned char *pDataInp ) { int nDi = 0; for( int nRi = 0; nRi < oMatFrameInp.rows; nRi++ ) { for( int nCi = 0; nCi < oMatFrameInp.cols; nCi++ ) { oMatFrameInp.data[oMatFrameInp.step[0] * nRi + oMatFrameInp.step[1] * nCi + 2] = pDataInp[nDi++]; // R oMatFrameInp.data[oMatFrameInp.step[0] * nRi + oMatFrameInp.step[1] * nCi + 1] = pDataInp[nDi++]; // G oMatFrameInp.data[oMatFrameInp.step[0] * nRi + oMatFrameInp.step[1] * nCi + 0] = pDataInp[nDi++]; // B } } } /**********************************************************************/ void MyfDispGstSampleInOpenCvWin( GstSample *pstGstSampleInp, gchar *szgWinTitle ) { if( !pstGstSampleInp ) { g_print( "*** Error: Could not make snapshot (may be due to eos)."); return; } GstCaps *pstGstCaps1; pstGstCaps1 = gst_sample_get_caps( pstGstSampleInp ); if( !pstGstCaps1 ) { g_print( "*** Error: gst_sample_get_caps fails to get sample cpas." ); return; } GstStructure *pstGstSt1; pstGstSt1 = gst_caps_get_structure( pstGstCaps1, 0 ); gint nFrameWidth, nFrameHeight; gboolean nGboolRes1; nGboolRes1 = gst_structure_get_int( pstGstSt1, "width", &nFrameWidth ); nGboolRes1 |= gst_structure_get_int( pstGstSt1, "height", &nFrameHeight ); if( !nGboolRes1 ) { g_print( "*** Error: gst_structure_get_int fails to get snapshot dimension."); return; } GstBuffer *pstGstBuffer1; pstGstBuffer1 = gst_sample_get_buffer( pstGstSampleInp ); GstMapInfo stGstMapInfo1; gst_buffer_map( pstGstBuffer1, &stGstMapInfo1, GST_MAP_READ ); cv::Mat oMatTstFrame; oMatTstFrame = cv::Mat::zeros( nFrameHeight, nFrameWidth, CV_8UC3 ); MyfCopyRGBbuf2CvMat( oMatTstFrame, stGstMapInfo1.data ); gst_buffer_unmap( pstGstBuffer1, &stGstMapInfo1 ); cv::namedWindow( szgWinTitle, CV_WINDOW_AUTOSIZE ); cv::imshow( szgWinTitle, oMatTstFrame ); } //******************************************************************************** int main( int argc, char *argv[] ) { gst_init( &argc, &argv ); // Describe pipeline gchar *szgPipelineDescStr1; szgPipelineDescStr1 = g_strdup_printf( "uridecodebin uri=\"file:///D:/QuickTimeSample.mov\" ! videoconvert ! videoscale ! appsink name=sink caps=\"video/x-raw,format=RGB\"" ); // Works for both frame and time seek //szgPipelineDescStr1 = g_strdup_printf( "uridecodebin uri=\"file:///D:/mpts_out.ts\" ! videoconvert ! videoscale ! appsink name=sink caps=\"video/x-raw,format=RGB\"" ); // NOT works for both frame and time seek // Create pipeline GstElement *pstGstElemPipeline1; GError *pstGErr1 = NULL; pstGstElemPipeline1 = gst_parse_launch( szgPipelineDescStr1, &pstGErr1 ); if( pstGErr1 != NULL ) { g_print( "could not construct pipeline: %s\n", pstGErr1->message ); g_error_free( pstGErr1 ); return( -1 ); } // Set to GST_STATE_PAUSED GstStateChangeReturn nStateChgRet; nStateChgRet = gst_element_set_state( pstGstElemPipeline1, GST_STATE_PAUSED ); if( nStateChgRet == GST_STATE_CHANGE_FAILURE ) goto Cleanup; nStateChgRet = gst_element_get_state( pstGstElemPipeline1, NULL, NULL, 5 * GST_SECOND ); if( nStateChgRet == GST_STATE_CHANGE_FAILURE ) goto Cleanup; // Set desired frame number to be displayed gint64 nDesiredMediaPosFrameNum = 120; // Init required variables GstElement *pstGstElemAppSink1; pstGstElemAppSink1 = gst_bin_get_by_name( GST_BIN( pstGstElemPipeline1 ), "sink" ); gboolean nGboolRes1; char *szgWinTitle; // Seek by GST_FORMAT_DEFAULT nGboolRes1 = gst_element_seek_simple( pstGstElemPipeline1, GST_FORMAT_DEFAULT, (GstSeekFlags) ( GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_FLUSH ), nDesiredMediaPosFrameNum ); if( !nGboolRes1 ) { g_print( "*** Error: gst_element_seek_simple by GST_FORMAT_DEFAULT failed!\n"); } // Read sample GstSample *pstGstSample1; pstGstSample1 = gst_app_sink_pull_preroll( (GstAppSink *) pstGstElemAppSink1 ); // or g_signal_emit_by_name( pstGstElemAppSink1, "pull-preroll", &pstGstSample1, NULL ); // Display sample szgWinTitle = g_strdup_printf( "Frame #%lld", nDesiredMediaPosFrameNum ); MyfDispGstSampleInOpenCvWin( pstGstSample1, szgWinTitle ); // Set desired position by time to be displayed gint64 nDesiredMediaPosNanoSec = 1000 * GST_MSECOND; // Seek by GST_FORMAT_DEFAULT nGboolRes1 = gst_element_seek_simple( pstGstElemPipeline1, GST_FORMAT_TIME, (GstSeekFlags) ( GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_FLUSH ), nDesiredMediaPosNanoSec ); if( !nGboolRes1 ) { g_print( "*** Error: gst_element_seek_simple by GST_FORMAT_TIME failed!\n"); } // Read sample GstSample *pstGstSample2; pstGstSample2 = gst_app_sink_pull_preroll( (GstAppSink *) pstGstElemAppSink1 ); // Display sample szgWinTitle = g_strdup_printf( "Time %" GST_TIME_FORMAT, GST_TIME_ARGS( nDesiredMediaPosNanoSec ) ); MyfDispGstSampleInOpenCvWin( pstGstSample2, szgWinTitle ); Cleanup: gst_element_set_state( pstGstElemPipeline1, GST_STATE_NULL ); gst_object_unref( pstGstElemPipeline1 ); g_print( "Press any key to finish...\n"); cvWaitKey( 0 ); return( 0 ); } Note: Include directories: D:\gstreamer\1.0\x86\include\gstreamer-1.0;D:\gstreamer\1.0\x86\include\glib-2.0;D:\gstreamer\1.0\x86\lib\glib-2.0\include;D:\opencv246\build\include\ Library directories: d:\opencv246\build\x86\vc11\staticlib;D:\gstreamer\1.0\x86\lib -- View this message in context: <a href="http://gstreamer-devel.966125.n4.nabble.com/How-to-read-an-specified-frame-from-an-MPEG-TS-video-file-tp4663005p4663079.html" target="_blank">http://gstreamer-devel.966125.n4.nabble.com/How-to-read-an-specified-frame-from-an-MPEG-TS-video-file-tp4663005p4663079.html</a> <div class="HOEnZb"><div class="h5">Sent from the GStreamer-devel mailing list archive at Nabble.com. _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.freedesktop.org">gstreamer-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a> </div></div></blockquote></div> <div> </div>-- Marcus Nascimento </div>